The role of Collembola in carbon and nitrogen cycling in soil

The article reviews recent publications dealing with relationships between Collembola, carbon and nitrogen turnover. Under field conditions, correlations between Collembola, total C and N are usually weak. More pronounced interdependences can be found with microbial parameters, especially when using multivariate statistics and sampling at high temporal resolution. Many manipulation experiments have revealed strong and usually positive impacts of Collembola on N mineralisation, soil respiration, leaching of dissolved organic carbon and plant growth. The effects are mostly indirect and depend on temperature, water content, substrate quality, population density, Collembola species, plant species and in particular on interactions with other soil biota. Key mechanisms are fungal feeding, distribution of fungal propagules, root herbivory and predation on nematodes. Omnivory is probably the prevailing feeding strategy in Collembola. Finally, a tentative conceptual model for arable soils is given, explaining the differing effects of Collembola on C and N turnover by switching feeding strategies according to environmental conditions.